From DE 103 31 358 A1 a device for efficient series production of a fuselage shell for an aircraft, which fuselage shell comprises fiber-reinforced composite materials, is known. In order to improve the strength of the fuselage shell it comprises stringers that extend so as to be spaced apart from each other. On a planar base support a grid of several supporting walls of different lengths is attached in such a manner that their ends form a semicircle, wherein said supporting walls are arranged relative to the base support at angles determined by the radius of the semicircle. Modular profiles are attached to the distal ends, which form the semicircle of the supporting walls, which profiles cover the spaces between the supporting walls, and with the outer surfaces of said profiles corresponding in the negative to the interior contour of the integral structural component to be manufactured. The grid of the supporting walls and the division of the modular profiles are designed in such a manner that the joining gap of the modular profiles in each case is arranged underneath the position of a stringer. After the complete construction of the component and of the auxiliary materials has been finished, a suitable laminating-bonding device is put in place with a precise fit above this mounting support, and the circumferential sealing compound that has previously been applied onto the vacuum foil is pre-compressed in such a manner that a vacuum-proof seal between the vacuum skin and the laminating-bonding device is created. Subsequently the construction is evacuated on the side of the laminating-bonding device.
The fuselage shell comprising stringers is manufactured with the device described above in that first the outer surfaces of the modular profiles are covered by a foil that is loosely in place. Subsequently, the hollow space formed by the spaces between the profiles is evacuated so that the foil is held by suction and is drawn in a form-accurate manner into the profile grooves and indentations. After this, the auxiliary materials can be placed onto the deep-drawn vacuum skin/foil. Subsequently, stringer profiles that have been embedded in support elements or form pieces are placed into the profile grooves covered by the vacuum skin/foil.
Positioning of the stringer takes place by way of the matching geometry of the depression and the form piece. Depending on the manufacturing method, all the skin layers comprising fiber-reinforced composite materials are placed, individually or as a packet, on outer surfaces, covered by the vacuum skin, of the modular profiles of the mounting support and the stringer profiles. Subsequently, an optimized quantity of a sealing compound is applied to the vacuum foil. By moving the thus prepared construction together, with a precise fit, with the laminating-bonding device the circumferential sealing compound is compressed in such a manner that a vacuum-proof seal between said vacuum skin/foil and the laminating-bonding device arises. In order to effect the transfer of the complete construction from the rigging device to the laminating-bonding device, the side of an additional rigging device is vented and subsequently a vacuum is applied on the side of the laminating-bonding device. As a consequence of this the entire construction is pressed at atmospheric pressure against the laminating-bonding device. Finally, the rigging device and the laminating-bonding device are moved apart, and the laminating-bonding device is rotated in order to be subjected to a curing process.
With quite strong opening angles of large fuselage shells this manufacturing solution is quite problematic. As a result of the strong opening angles, during insertion into a laminating-bonding device with the sticky-wet skin thereon, the auxiliary materials and the stringer base areas can rub against the outer positions, so that the mold surface needs to be designed so as to be slightly smaller. To prevent the stringers and the auxiliary materials from bridging the required gap in an uncontrolled manner during transfer within the laminating-bonding device, in which gap they are simply taken along with the enveloping vacuum foil, defined leading-in of the stringers and of the auxiliary materials is necessary.
Depending on the design of the stiffening elements in longitudinal direction (stringers), which can, for example, be the so-called omega-stringers (hat profile) or T-stringers, an undercut occurs, which makes it impossible for the rigging device and the laminating-bonding device to move apart from each other. In the case of omega stringers this depends on the angles of the profile and the opening angle of the shell. In the case of a T-stringer the undercut point occurs practically immediately when the geometry of the cavity precisely corresponds to that of the stringer. The cavities for accommodating the stringers can be cut free in such a manner that the moving apart of the rigging device and the laminating-bonding device is ensured. However, in the case of large opening angles a further problem then arises, namely that of affixing the auxiliary materials. They are usually placed onto the free region between the stringer cavities and are affixed in that position. If the stringer cavity is cut free strongly, hardly enough space remains for neat positioning of the auxiliary materials. Furthermore, the outer geometry of the supporting element or of the form piece is determined by the undercut angle, i.e. the form pieces surrounding the stringer become so large that they cover the complete skin, in other words extend to the next stringer profile. This is problematic from the point of view of manufacturing technology.